This invention relates to a rotary vane reverse Brayton cycle cooling system.
The U.S. Pat. Nos. to Edwards, 3,686,893; 3,913,351; and 3,977,852, describe cooling systems which operate on a reverse Brayton cycle. The article "Performance of a New Positive-Displacement Air Cycle Machine" by R. E. Smolinski and Dr. L. L. Midolo given at an American Institute of Aeronautics and Astronautics Conference, Sept. 27, 1976, describes an air cycle machine wherein the vanes are supported on bearings which ride on a cam track to take up the radial vane loads.
In environmental control systems for aircraft it is desirable to obtain maximum cooling with minimum weight or to have a high cooling/weight ratio. In a reverse Brayton cycle cooling system more cooling for the same physical volume can be obtained by operating the device at higher velocities. Increasing the velocity of prior art vanes causes greater deflection of the vanes and increased bearing wear and could cause destruction of the apparatus. The Aeronautics and Astronautics Conference article suggests the use of featherweight vanes. However, many light weight materials will bend at high velocities and would contact the chamber wall and result in intolerable wear on the vanes. Most high strength light weight materials are abrasive and have poor wear characteristics.